Apparatus for making maps from aerial photographs



Aug. 17, 1937. E. R. SWANSON 2,090,270

APPARATUS FOR MAKING MAPS FROM AERIAL PHOTOGRAPHS Filed June 10, 1935 4 Sheets-Sheet l //v IE/v To 2.

4 r ram/En i T fit ff- Eemssr E W E. R. swANsoN 2,090,270

APPARATUS FOR MAKING MAPS FROM AERIAL PHOTOGRAPHS.

Filed June 10, 1935 4 Sheets-Sheet 2 Aug. 17, 1 937.

Aug. 17, 1937 E. R. SWANSON APPARATUS FOR MAKING MAPS FROM AERIAL PHOTOGRAPHS 4 sheets-sheet :5

Filed June 10, 1935 INVENTOE kNEs 7' R. WANJZM flrroeusr.

Aug. 17, 1937. E. R. SWANSON APPARATUS FOR MAKING MAPS FROM AERIAL PHOTOGRAPHS Filed June 10, 1935 4 Shasta-Sheet 4 t'RNEsr Patented Aug. 17, 1937 UNITED STATES APPARATUS FOR MAKING MAPS FROM AERIAL rno'roGnArns Ernest R. Swanson, St. Louis, Mo. Application June 10, 1935, Serial Nb. 25,802'

12 Claims.

My invention relates to apparatus for making maps from aerial photographs and more particularly .to such apparatus wherein .an image of the photograph is projected onto a plane surface to be traced so that a map of the area included in the photograph may be produced on such tracing.

Heretofore, attempts have been made to produce an apparatus of this type which would be efiicient, compact, accurate and simple in opera tion, but such devices as have been manufactured and used have been intricate, bulky, inefficient and expensive in design. Also, such apparatus as has been used did not allow accuracy in the maps produced therewith because contours of the terrain represented in the aerial photograph could not be included in the map without involved manipulation and computation. Furthermore, the projected fiat image made for errors and resultant distortion which necessitated ad- 50 justments and computations to rectify partly these conditions.

In an apparatus of this type as heretofore used the image was projected downwardly upon the work table so that the draftsman tracing the g5 projected image, as described above, cast his own shadow on'the' work table and the tracing was accomplished with great difllculty and high possibility of error. In some devices the image was projected into a vertical plane and as a result the draftsman worked in an unnatural and uncomfortable position.

Having in mind the deficiencies of the prior used devices the objects of my invention are to provide an apparatus and method of using such apparatus for making maps from aerial photographs whereby results of great accuracy will be obtained; to provide such apparatus which is simple and cheap in manufacture and operation; to provide an apparatus which allows the draftsman to work in comfort; and to providean apparatus whereby the resultant map will accurately show the contour of the terrain photographed without necessitating intricate adjustments and computations.

In the accompanying drawings wherein similar characters are used to designate similar parts, my invention is shown embodied in an apparatus of the dual projection type wherein a pair ofprojectors are used to project a fused image from :6 aerial photographs of overlapping sections of country. In the drawings, Fig. 1 shows the apparatus in elevation; Fig. 2 is a plan view of the apparatus as shown in Fig. 1; Figs. 3 and 4 show the arrangement for driving the various 5 shafts which operate adjustments of the parts;

Figs. 5, 6 and '7 are details of the mechanical parts for effecting automatic focus of the projectors, all as described fully hereinafter in the specification; Figs. 8, 9, I0 and 11 show the means used to complete fusion of the images from the projectors; and Figs. 12 and 13 show a contouring device which when used with the other parts of the apparatus assures production of an accurate topographic map.

Referring to the figures in' the embodiment shown, the supporting frame for the v-rious parts of the deviceincludes a top I carried by legs 2. The top has the center portion thereof cut out and otherwise adapted to receive a transparent plate 3 upon which the dual image from the projectors is focused and which provides a fiatwork surface arranged at the proper height for tracing the image, all as shown in Figs. 1 and 2 and for the purposes more fully hereinafter described. At each end of the device and preferably midway between the sides thereof is arrangeda vertically extending guide 4 upon which the carriage 5 for the projectors 5 is raised and lowered. Preferably, the side edges of the guide 4 are provided with teeth to form a rack,-for the purpose hereinafter mentioned. Arranged inwardly from each of the guides l is a shaft 1 threaded in a boss Bat an end of, the carriage 5 so that the carriage may be raised or lowered. by rotation of the shafts I. The lower ends of the shafts I and guides 4 may be maintained in predetermined position by the stringers"! extending between the legs.

At the upper ends of the shafts I are fixed sprockets l0 adapted to engage a chain Ii which extends inside of the frame of the top i and runs over sprockets i2 carried on brackets i3 near the corners of the table. However, one of said sprockets as at i2 is driven through beveled gears i4 and shaft i5 by a hand wheel I, preferably, set fiush in the side frame of the top i and having a knob II to facilitate rotation. Itv will be understood clearly that rotation of the wheel iii in either direction will move the chain ii and, in turn, rotate the shafts I to'raise or lower the carriage 5 on the guides l and, thereby, to increase or decrease the size of the image projected on the transparent plate 31 by V l the projector 6. a

However, to obtain best results in using my device it is desirable that as the carriage 5 is '10 2| and 22, stub 23 and beveled gears 24 and 25.

The gears H3 at opposite ends of the carriage 5 are arranged on the same side of the guides 4 so that the shaft 20, of course, will be driven in the same direction by both driving means.

Idler gears 3| may be included to balance the movement along the guides 4.

Each projector includes a housing 25 slidably mounted on suitably arranged parts of the carriage 5 and the projector also includes a lens support 21 for the front end of a bellows 23 extending between a plate holder 29 or 29 at the front end of a housing 26 and a lens mounting 30. In the form of device shown, the lens are used in conjunction with a prism so that the image is projected at a right angle to the axis of the projector.

The mechanism for automatically focusing each projector by means of the shaft 20 is shown in detail in Figs. 5, 6 and '7. Keyed onto 30 the shaft 20 so as to be slidable along the shaft, but to be rotated thereby is a beveled gear 32 which is maintained in mesh with a ring gear 33 carried on the bottom plate 34 fixed to the lens support 21.

35 predetermined position relative to the ring gear 33 by the support 21. The bottom plate 34 is slidably mounted relative to the main housing 25 of the projector. On the upper face of the ring gear .3 is arranged an eccentric groove 35 adapted to receive a pin 31 fixed in the collar 38.

Extending from the collar 33 and secured thereto is a link 39 which has its end opposite the end fixed to the collar secured to the lower part of the housing 26. The groove 36 is shaped and the speed of rotation of the ring gear 33 is adjusted so that as the carriage 5 is raised or lowered, in the manner described above, the

ring gear 33 will be rotated and the grove 35 will move the collar 38 along the shaft 23 and the co-action of the pin 31 in the groove 35 will cause the projector housing 23 and lens support 21 to be moved relative to one another so that the focus of the projectors will be varied. By careful adjustment of the parts the device may be arranged so that the projectors will be properly focused for any vertical adjustment of the carriage. When the carriage 5 is raised or lowered to increase or decrease the size of the image cast on the plate 3 it is-necessary that the images from the two projectors be properly merged or fused one into the other. To this end,

it is necessary that the distance between the projector 5 be varied. To accomplish this, I provides. shaft 43 extending vertically and adapted to be rotated by a wheel 4|, preferably, set flush in the top I and having thereon a knob 42. Keyed on the shaft 43 so as to be slidable therealong but to be rotated thereby, is a beveled gear 42 maintained in mesh with the beveled gear 43 by a bracket 44 carried by the carriage 5. The beveled gear 43 is fixed to the shaft 45 which is supported at the center of the carriage 5 by a block 46. The shaft is threaded in opposite directions on each side of the centerblock so that 75 each threaded portion of 'the shaft passes The gear 32 is maintained in through and is threaded in the lens support 21 of a projector. When the shaft 43 is rotated by the hand wheel 4| the projectors 5 will be moved towards or away from one another according to the direction of rotation of shaft 40 and, in turn, shaft 45.

It is sometimes necessary for complete fusion of the images that the plates containing the aerial views be shifted in the projectors and, therefore, I provide mechanism as shown in detail in Figs. 8, 9, 10 and 11, whereby the plate holder 29 for one projector may be rotated with its contained plate and the plate holder 29 for the other projector may be moved in a path at right angles to the axis of the projector. The plate holder 29 is moved by a vertical shaft 41 through a worm wheel 43 keyed thereon,.pinion 43, shaft 50, and gear 52 in mesh with ring gear 53 associated with the plate holder 23. The gear 52 is keyed on the shaft 50.

The plate holder 29* is moved at right angles to the axis of the projector by the shaft 54, worm wheel 55 keyed thereon and meshing with pinion 56 fixed to the shaft 51, pinion 53 keyed on shaft 51 and in mesh with rack 53 associated with plate holder 23.

The shafts 41 and 54 are rotated in a direction to effect the proper movement of the plate holders 29 and 23" by hand wheels 60 and 6|, respectively. These hand wheels are preferably set flush in the top I and are provided with knobs 52.

If the parts of the device are arranged as by projecting the two images with rays of different complementary colors and by causing the rays to intersect in space and the images to be focused and fused on a given surface. This composite projection is then viewed stereoscopically through filter spectacles of the same density and complementary colors as used in the projection filters, thereby rendering the area plastically visible to the operator and permitting direct interpretation and generation of a map by the tracing of the topographic features and terrain as disclosed by the viewed image.

Therefore, the lens of the projectors 3 are provided with filter screens of different colors so that the rays will be projected in different compleme'ntary colors. The filter spectacles by which the fused image is viewed are not shown.

When my new and improved device in. the embodiment shown is to be used to produce a topographic map a sheet of tracing cloth or paper is fastened onto the top I to register with the transparent plate 3. Plates of overlapping aerial views of .the terrain to be mapped are inserted in the plate holders 23 and 23' and the projector carriage 5 is raised or lowered by manipulation of the hand wheel I. until the image cast upon the transparent plate 3 and visible through the tracing material is of the desired size. By the term "plate" as used herein. I mean a translucent reproduction or any other form of print which may be projected by a suitable or lowered the projector 6 will be focused automatically at all times and for all vertical adjustments of the carriage the dual images will be clear cut as projected into the plane of the 5 transparent plate 3.

However, for best results and for the reasons described above there should be perfect fusion of the two projected images and, such fusion may be easily secured by moving the projectors 6 and 10 the images projected therefrom towards or away from one another by manipulation of the hand wheel 4|. Exact fusion then may be obtained by moving the plate holders 29 and 29 and their carried plates by manipulation of the hand wheels 5 60 and BI. The two images in rays of complementary colors upon proper manipulation and adjustment of the parts will be in perfect fusion and the resultant dual or fused image when viewed through filter spectacles quickly and easily 0 may be traced on the tracing material so that the topography of the pictured terrain will be accurately shown.

I have found that it is necessary that a topographic map should include indications of varying elevations of the terrain and, althoughthe variances may be computed from field notes this is a long and tedious procedure. Asthe contour of the country is generated fully by the projection method described above I have found that elevation indicia may be placed upon the tracing if a contouring device, one embodiment of which is shown in Figs. 12 and 13, is used in conjunction with the mapping apparatus described herein.

In the embodiment shown the contouring device includes a foot 63 supported on smooth knobs 64. Extending upwardly from and fixed to the foot 63 is a standard 65 graduated as at. 56. Slidably mounted along guide posts 61 and the: standard 65 is a frame 68 which may be moved into any desired adjusted position by rotating the thumb screw 69 carried by the yoke 10 and having at its inner end a small gear I! in mesh with the rack 16 formed on the standard 65. The thumb screw 69 may be held in adjusted position by a lock nut II associated therewith. The frame 68 supports a transparent plate indicated at 12. This plate has, preferably in the center thereof, a floating ground mark 13 Carried at the bottom of the device is a holder 14 for a pencil 15 which pencil is adapted to bear and mark upon the tracing material on the transparent plate 3. When the contouring device is placed on the tracing material and when the image is viewed through the filter spectacles as fully set forth aboveyby raising or lowering-the frame 68 the floating ground mark 13 will appear to be above, below or on the ground as generated by the fused image from the projectors. The floating ground mark 13 is fixed on a pointof known elevation 0 and the graduation at which the frame is set is noted. As the contouring device is moved over the tracing if the ground mark 13 appears to'be above the ground the operator knows that at that point the elevation is less than that at the known 65 point for' whichthe contouring device. has been set. ground, in turn, it is known that the elevation at that point is higher than the point for which the mark has been set. If the elevation for two 7 points is known after-the ground mark I3 has been set to register with the two known points the difference in graduations at which the ground mark registers with the two known elevations may be calibrated into hundreds or thousands of feet and the elevation of any'part of the terrain If the ground mark 13 appears below the may be determined quickly by registering the floating mark 13 therewith and then computing the relative elevations on the calibrations 66.

In the accompanying drawings and in the above description, I have shown one embodiment of my invention, but it should be understood that.

apparatus made according to my ideas may take many forms without deviating from the spirit of my invention as included in the appended claims.

What I claim as new and desire to secure by Letters Patent, is:-

1. In an apparatus of the class described, the combination of a supporting frame including a flat work surface, a projector carriage adjustably supported to be movable away from or toward said work surface, a projector mounted on said carriage and arranged to project onto said work .surface an image from a plate adjusted therein, means for moving said carriage relative to said work surface, said projectorincluding a lens and said plate, a cam plate having an eccentric groove formed therein, a link having apin associated in said groove, power transmitting mechanism whereby said cam plate will be rotated when said carriage is raised or lowered, and said cam and said link being positioned and arranged whereby when said cam is rotated said lens and said plate will be moved relative to each other whereby the projected image will be focused automatically on said work surface at any adjusted position of said carriage.

2. In an apparatus of the class described, the combination of a supporting frame including a transparent panel, a pair of guides arranged at substantially right angles to said panel and extending downwardly therefrom, a projector carriage slidably mounted on said guides whereby jector including a lens and said plate, one of said guides having a rack formed along an edge thereof, a gear mounted on said carriage and in mesh with said rack whereby said gear will be rotated when said carriage is raised or lowered, a shaft fixed to said gear and adapted to rotate a cam plate, a link having a pin associated with said cam plate, and said cam plate and said link being positioned and arranged whereby when said cam is rotated by raising or lowering said carriage said lens and saidplate will be moved relative to each other whereby the projected image will be focused automatically on said panel at any adjusted position of said carriage.

3. In an apparatus of the class described, the Y combination of a supporting frame including a flat work surface, a projector carriage adjust- ,ably supported relative to said work surface, a

ably supported relative to said work surface, a,

pair of projectors mounted on said carriage and each arranged to project onto said-worksurface an image from a plate adjusted-therein, each of said projectors including a plate holder for said plate and a lens, means for moving said carriage away from or toward said work surface,

5 and manually operable means for effecting adjustments of said projectors relative to each other and of said plate holders whereby the images as projected on said work surface may be fused.

i0 5. In an apparatus of the class described, the

combination of a supporting frame including a flat work surface, a'projector carriage adjustably supported to be movable away from or toward said work surface, a pair of projectors mounted on said carriage and each arranged to project onto said work surface an image from a plate adjusted therein, each of said projectors including a plate holder for said plate and a lens, the plate holder of one of said projectors being arranged to be rotated in a plane substantially at right angles to the axis of said projector, the plate holder of the other of said projectors being arranged to be moved transversely of the axis of said projector, and means operable from said work surface for moving said plate holders whereby the images as projected on said work surface may be fused.

6. In an apparatus of the class described, the combination of a supporting'frame including a flat work surface a projector carriage adjustably supported to be movable away from or toward said work surface, a pair of projectors mounted on said carriage so as to be movable relative to each other and each arranged to project onto said work surface an image from a plate adjusted therein, means for moving said carriage relative to said work surface, each of said projectors including a plate holder for said plate and a lens, the plate holder of one of said pro- 40 jectors being arranged to be rotated in a plane substantially at right angles to the axis of said projector, the plate holder of the other of said projectors being arranged to be moved trans versely of the axis of said projector, and means operable from said work surface for moving said projectors relative to each other and for moving said plate holders whereby the images as projected on said work surface may be fused.

7. In an apparatus-of the class described, the combination of a supporting frame including a flat work surface, a projector carriage adjust-- ably supported to be movable away from or to-- ward said work surface, a pair of projectors mounted on said carriage and each arranged to project onto said work surface an image from a plate adjusted therein, each of said projectors including a plate holder for said plate and a lens, the plate holder of one of said projectors being arranged to be rotated in a plane substantially at right angles to the axis of said projector, the plate holder of the other of said projectors being arranged to be moved transversely of the axis of said projector, and means operable from said work surface for moving said plate holders where- 55 by the images as projected on said work surface may be fused, and means operating automatically upon adjustment of said carriage for focusing the projected fused image on said work surface whereby said projectors will be focused automati- 7 cally at any adjusted position of said carriage.

8. In an apparatus of the class described, the combination of a supporting frame including a flat work surface, a projector carriage adjustably supported to be' movable away from or toward 75 said work surface, a pair of projectors mounted on said carriage so as to be movable relative to each other and each arranged to project onto said work surface an image from a plate adjusted therein, means for moving said carriage relative to said work surface, each of said projectors including a plate holder for said plate and a lens, the plate holder of one of said projectors being arranged to be rotated in a plane substantially at right angles to the axis of said projector, the plate holder of the otherof said projectors being arranged to be moved transversely of the axis of said projector, and means operable from said work surface for moving said projectors relative to each other and for moving said plate holders whereby the images as projected on said work surface may be fused, and means operating automatically upon adjustment of said carriage for focusing the projected fused image on said work surface whereby said projectors will be focused automatically at any adjusted position of said carriage.

9. In an apparatus of the class described, the combination of a supporting frame including a transparent panel, a pair of guides extending vertically downwardly belowsaid panel, a pro-v jector carriage adjustably mounted on said guides so as to be movable away from or toward said panel, a pair of projectors mounted on said carriage so as to be movable relative to each other and each arranged to project onto said panel an image from a plate adjusted therein, a plate holder for each of said projectors, and manually operable means for moving said carriage relative to said work surface and means for effecting adjustments of said projectors relative to each other and of said plate holders whereby the images as projected on said work surface may be fused.

10. In an apparatus of the class described, the

projectors relative to each other and .of said plate holders whereby the images as projected on said work surface may be'fused, and means oper-' ating automatically upon adjustment of said carriage for focusing the projected fused image on said panel whereby said projectors will be focused automatically at any adjusted position of said carriage.

11. In an apparatus of the class described, the combination .of a supporting frame including a flat work surface,a projector carriage adjustably supported relative to said work surface, a' pair of projector housings mounted on said carriage to be ,movable therealong relative to one another, a

each of said housings including a projector .ar-

ranged to project onto the same area of said work.

surface an image from a plate adjusted therein and said housing also including a single operating v means controlled by themovement of said carriage for automatically focusing and fusing the image from said projectors on said surface at any adjustedposition of said carriage relative to said work surface.

12. In an apparatus of the kind described, the combination of a supporting frame including a Cir flat work surface, a projector carriage mounted on said supporting frame so as to be movable away from or toward said work surface, a pair of projector housings mounted on said carriage to be movable therealong relative to one another, a single manuallyoperable means for moving said housings toward and away from each other, on said carriage and for moving said carriage relative to said work surface, each of said housings a plate adjusted therein, a shaft mounted on said carriage and arranged to be rotated by movement of said carriage away from or toward said work surface and for moving said housings and each of said housings including focusing means controlled by rotation of said shaft whereby the image from each of said projectors willbe focused automatically and fused on the same area of said worl; surface in any adjusted position of said carriage.

ERNEST R. SWANSON. 

